Portable computers such as notebook computers typically have a plastic top cover for housing and protecting a flat-panel display. In most cases, the flat-panel display is secured to the back or rear surface of the top cover. Along one edge of the top cover, the top cover is pivotably secured to a base unit with two hinges. The base unit usually has a plastic base unit housing to which the hinges are mounted and includes a keyboard on the upper surface of the base unit. The hinges allow the top cover to be opened and closed over upper surface (and hence the keyboard) of the base unit. When in the closed position, the top cover protects both the flat-panel display and the keyboard. To use the computer, the top cover is pivoted upwardly and tilted backward, relative to the base unit, to allow visual access to the flat-panel display and physical access to the keyboard.
Often, the top cover twists while pivoting. Twisting of the top cover can bind the hinges and inhibit the ability of the top cover to pivot smoothly. In addition, since the hinges are typically mounted to plastic surfaces of the base unit housing, alternating forces exerted onto those plastic surfaces by the hinges can fatigue the plastic over time and result in breakage.
The present invention is directed to a hinge system for a portable computer for pivotably securing a top cover to a base unit while preventing twisting of the top cover and breakage of the base unit housing. The hinge system includes a first base unit hinge member for mounting to the base unit. The first base unit hinge member has proximal and distal mounting portions which are angled relative to each other. The proximal and distal mounting portions are each securable to a surface of the base unit for distributing stress exerted on the base unit by the first base unit hinge member. A first pivoting top cover hinge assembly is secured to the first base unit hinge member. The first top cover hinge assembly mounts to the top cover.
In preferred embodiments, the first top cover hinge assembly includes a lower pivoting piece mounted to the first base unit hinge member. The lower pivoting piece is pivotably secured to an elongate stiffening member. The elongate stiffening member is secured to the top cover to stiffen the top cover. Specifically, the lower pivoting piece is pivotably mounted to an upper pivoting piece by a shaft. The upper pivoting piece is secured to the elongate stiffening member. The lower pivoting piece includes a tongue for insertion into a cavity within the first base unit hinge member for securing thereto. The lower pivoting piece further includes a mounting flange for securing to a top surface of the first base unit hinge member. The tongue and mounting flange are secured to the first base unit hinge member by fasteners oriented at right angles to each other.
The present invention hinge system typically includes a second base unit hinge member for mounting to the base unit spaced apart from the first base unit hinge member. The second base unit hinge member has proximal and distal mounting portions which are angled relative to each other. The proximal and distal mounting portions are each securable to a surface of the base unit for distributing stress exerted on the base unit by the second base unit hinge member. A second pivoting top cover hinge assembly is secured to the second base unit hinge member for mounting to the top cover spaced apart from the first top cover hinge assembly. The second top cover hinge assembly includes a lower pivoting piece mounted to the second base unit hinge member. The lower pivoting piece is pivotably secured to an elongate stiffening member for securing to the top cover to further stiffen the top cover. The first and second base unit hinge members are typically mounted to first and second corners of the base unit. The proximal and distal mounting portions of the base unit hinge members are preferably at right angles to each other and are secured to a bottom panel of the base unit.